Description: The investigators propose to develop a aerosol delivery system containing genistein and a b-agonist (broncho-dilator) for the treatment of cystic fibrosis (CF). Preliminary studies have shown that genistein interacts with the CF transmembrane conductance regulator which is defective in patients with CF as a result of a specific mutation. Genistein raises the bioelectric potential differences (PD) across the nasal membrane and increases chloride transport. These investigators are directed at developing an aerosol by evaluating the dose and pharmacokinetics of genistein in regard to altering PD, performing a repetitive dose experiment with the aerosol, and finally performing safety studies with this aerosol. A final study will investigate the efficacy of using oral genistein supplements to alter the nasal membrane PD.